It is tough to get a ball python visibly overweight but that said it can be done. Also they don't have to appear overweight to have fatty deposit around vital organs which can cause medical problems and significantly shorten there life. No they will not stop eating if they are over weight but you can cause a Ball python to go off feeding due to over feeding. Although ball pythons good off feeding for no reason at all so go figure that. I would back off to every 7 days how old is your ball python right now and how much is it weighing in at. If you feed a larger meal to ball python they tend to fatten up were as if you feed smaller meals with less girth on them you will have a bit more of a slender ball.

Chuck